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Session F7 - Structure, Dynamics and Reactions at Liquid Interfaces-II.
MIXED session, Tuesday morning, March 19
Room 261, America's Center
The goal of our work is the elucidation of the surface structure of liquids on the molecular level. We use several electron spectroscopies and related techniques. In photoelectron spectroscopy the observation depth is governed by the mean free path of the photoelectrons which in turn depends on the kinetic energy. Using synchrotron radiation as source of photons the energy and thus the observation depth can be controlled. Such measurements allow to reconstruct concentration depth profiles on a scale length of ca. 0.2 nm. Perfect surface sensitivity is achieved by MIES (= Metastable Induced Electron Spectroscopy) because the metastable helium atoms do not penetrate into the liquid. Recently we have applied ISS (= Ion Scattering Spectroscopy) to liquid surfaces, again a technique of perfect surface sensitivity which yields the elemental composition. Among the systems studied are pure polar solvents \footnote[2]H. Morgner and W.A. Müller Mol. Phys. 57 (1986) 623, H. Morgner, J. Oberbrodhage and M.Wulf J. Electr. Spectr. Rel. Phen. 61 (1993) 183-92, liquid mixtures\footnote[3]H. Morgner, J. Oberbrodhage, K. Richter and K. Roth Mol. Phys. 73 (1991) 1295 - 1306, H. Morgner and M. Wulf J.Electr.Spectr.Rel.Phen. (1995) in print, solutions of surface active salts \footnote[4] H. Morgner and J. Oberbrodhage J. Phys.: Condens. Matter 7 (1995) 7427-7441, H. Morgner, J. Oberbrodhage, K. Richter and K. Roth J. Phys.: Condens. Matt. 3 (1991) 5639 - 55 and the spontaneous formation of tenside films on liquid surfaces \footnote[5]H. Morgner, J. Oberbrodhage and K. Richter Mol. Phys. 76 (1992) 813-22, H. Morgner, K. Richter and M.Wulf Mol. Phys. 79 (1993) 169-177.
